1. Field of the Invention
The present invention relates to a display device, and in particular to a display device in which the shapes of a display area and a substrate of a display panel having a touch sensor function are not rectangular.
2. Description of the Related Art
A touch-panel built-in display panel in which a display panel is integrated with a touch panel, that is, a so-called in-cell type display device, is mounted in a variety of electronic devices.
In an active matrix display panel, for example, a scan line is arranged for every pixel row in a display area where pixels are two-dimensionally aligned in a matrix, and a video line is arranged for every pixel column so as to intersect the scan line. Further, circuits for inputting signals to the scan lines and the video lines are arranged in a frame area outside the display area on the substrate of the display panel. Specifically, a pixel row is selected in response to a signal applied to a scan line, and a video signal is inputted to the pixel selected from a video line.
An electrostatic capacitance type touch panel has a detection electrode and a drive electrode. A drive signal is applied to the drive electrode to detect an object, such as a finger, etc., approaching and touching the touch panel, based on an output signal from the detection electrode. In a touch panel built-in display device, a common electrode for applying common potential to the respective pixels of the display panel is divided into a plurality of portions to be used also as drive electrodes of the touch sensor. Circuits for inputting signals to the drive electrodes as well are arranged in the frame area of the substrate.
Generally, the display area of a conventional display panel is rectangular. FIG. 12 schematically shows a layout of a conventional in-cell type display panel. In a rectangular display area 2, scan lines 4 are arranged extending in the horizontal direction (the direction of a pixel row), while video lines 6 are arranged extending in the vertical direction (the direction of a pixel column). Further, a plurality of drive electrodes 8 are arranged in the display area, each having a width covering a plurality of pixel rows and extending in the horizontal direction. In the frame area 10, scan circuits 12 for applying signals to the scan lines 4 and switch circuits 14 and shift register circuits 16, as circuits for applying signals to the drive electrodes 8, are arranged along the left and right sides of the display area 2, and video signal transmission lines and selectors 20 for inputting video signals from a driver IC 18 to the video lines 6 are arranged along the lower side of the display area 2. That is, the circuits for supplying signals to the signal lines and electrodes extending in the horizontal direction in the display area 2 are arranged along a vertical side of the display area 2 with which the ends of the signal lines, etc., are aligned, while the circuits for supplying signals to the signal lines etc., extending in the vertical direction in the display area 2 are arranged along the horizontal side of the display area 2 with which the ends of the signal lines etc., are aligned. That is, these circuits are arranged along respective different sides of the rectangular shape.